地中海贫血是一组遗传性单基因疾病,其特征在于血红蛋白四聚体的一个或多个珠蛋白链亚基的合成缺陷。δ-β(δβ-)地中海贫血在β珠蛋白基因簇中存在大量缺失,涉及δ-和β-珠蛋白基因,导致δ-和β-珠蛋白链的合成缺失或减少。这里,我们使用串联质谱的直接珠蛋白链分析来诊断δβ-地中海贫血。根据临床和血液学评估,招募了两名来自无关家庭的病例进行研究。使用液相色谱-串联质谱法(LC-MS/MS)分析从来自两个受影响的个体及其父母的红细胞沉淀中提取的蛋白质的胰蛋白酶消化后获得的肽。质谱分析显示δ严重降低,β,和Aγ珠蛋白在受影响的个体中具有增加的Gγ珠蛋白。根据我们的结果,对受影响个体的纯合状态和父母的杂合状态下的Gγ(Aγδβ)0-地中海贫血进行了诊断。使用多重连接依赖性探针扩增(MLPA)在遗传水平上证实了诊断。我们的发现证明了使用LC-MS/MS直接定量珠蛋白以定量反映珠蛋白产生变化的单个珠蛋白的实用性。这种方法可用于准确及时地诊断血红蛋白病,包括罕见的变种,现有的诊断方法提供不确定的结果。
Thalassemias are a group of inherited monogenic disorders characterized by defects in the synthesis of one or more of the
globin chain subunits of the hemoglobin tetramer. Delta-beta (δβ-) thalassemia has large deletions in the β
globin gene cluster involving δ- and β-
globin genes, leading to absent or reduced synthesis of both δ- and β-
globin chains. Here, we used direct globin-chain analysis using tandem mass spectrometry for the diagnosis of δβ-thalassemia. Two cases from unrelated families were recruited for the study based on clinical and hematological evaluation. Peptides obtained after trypsin digestion of proteins extracted from red blood cell pellets from two affected individuals and their parents were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Mass spectrometric analysis revealed a severe reduction in δ, β, and Aγ globin proteins with increased Gγ
globin protein in the affected individuals. The diagnosis of Gγ(Aγδβ)0 -thalassemia in the homozygous state in the affected individuals and in the heterozygous state in the parents was made from our results. The diagnosis was confirmed at the genetic level using multiplex ligation-dependent probe amplification (MLPA). Our findings demonstrate the utility of direct globin protein quantitation using LC-MS/MS to quantify individual
globin proteins reflecting changes in
globin production. This approach can be utilized for accurate and timely diagnosis of hemoglobinopathies, including rare variants, where existing diagnostic methods provide inconclusive results.